1. Field of the Invention
The present invention relates to an improved portable crushing apparatus adapted to be moved by a tractor.
2. Description of the Prior Art
In recent years, the load-and-carry method has been used at a quarry or the like. In the method, a primary crushing apparatus is installed near a working face and stones are carried by a shovel loader to the crushing apparatus and dumped into it. In such a method, a self-propelling crushing apparatus with a crawler or a portable crushing apparatus adapted to be carried to a work place by a tractor is used.
FIG. 1 shows a conventional self-propelling crushing apparatus which has a crawler 1, a frame 2 mounted on the crawler 1, a crusher 3 mounted on the frame 2, a feeder 4 with a hopper 5 provided at the rear of the frame 2 to carry the material to be crushed to the crusher 3, a swivel conveyor 6 provided at the front of the frame 2 to discharge the crushed material out of the apparatus, and a discharge conveyor 7 for carrying the crushed material from the crusher 3 to the swivel conveyor 6.
Since such a self-propelling crushing apparatus has a crusher 3 and all the necessary equipment mounted on the crawler 1, the entire apparatus is of a considerable height and a long feeder 4 is required. Another problem is that the load due to the vibration of the crusher 3 is always applied to the crawler 1, affecting unduly its operation. This puts a limitation on the size of the crusher. Also, the use of a crawler increases the cost of the entire apparatus.
Further, such a conventional crushing apparatus has some shortcomings about its operation. Because of high position of the hopper, an inclined or raised portion 8, from which the material to be crushed is dumped by a shovel loader 9 into the hopper 5, has to be placed on the ground. This decreases the rate of efficient operation. Further, when moving the crushing apparatus from one location to another, the old raised portion 8 has to be leveled off and another raised portion has to be installed at the new location. This step also results in a substantial decrease in the work efficiency.
FIG. 2 shows another conventional crushing apparatus which has two trucks 10, 11 with wheels 12, 13, respectively, having rubber tires. One truck 10 carries a crusher 3 and another truck 11 carries a hopper 5' and a feeder 4'.
This apparatus, too, is of a considerable height and requires a long feeder 4'. Thus, a raised portion 8 is needed. Further, in this type, alignment of the trucks 10, 11 to each other is very troublesome. It takes much time to align the supply port of the crusher 3 with a discharge port of the feeder 4'.